如今地球表面平均温度为15摄氏度
700 million years ago,it was much colder.
7亿年前，要冷得多了
That average surface temperature plummeted to minus 50,5-0 degrees celsius.
平均表面温度降至负50摄氏度
Most of the Sun's heat was reflected back to space.
太阳热量大多数都会被反射回太空
it looked like that the Earth might never heat up again.
看起来地球将永远无法回暖
but clearly something happened.
但显然发生了某些事情
It was volcanoes that came to the rescue.
出手挽救的正是火山
They eruped with tremendous force,
火山喷发
even blasting through the ice sheets that covered much of the planet.
突破覆盖整个行星厚厚的冰层
It must been an extraordinary time.
那必定是个非凡时代
The nearest we have experienced was in 2004
与其最接近的是2004年
when an eruption was filmed busting through an ice sheet in Central Iceland.
当时冰岛中部一次火山喷发 即突破了冰层，并被摄像记录
This is what would have happened millions of years ago,
亿万年前的情况\N必定也是如此
but on a global scale.
而且是全球规模的
The heat from volcanoes would have melted holes in the ice,
火山的热量肯定在冰层中熔化了一些孔洞
but that is not what saved our planet.
但那并不是地球得救的原因
it was the tons of carbon dioxide gas it released that did the trick.
功绩属于火山释放的数以吨计的二氧化碳
